Monday, March 25, 2013

Seola Beach

For a shoreline once characterized by eroding coastal bluffs, spilling gravel and sand onto the beach, Seattle has remarkably few of these places left. They exist on the north and south sides of Discovery Park and there is a short stretch on the south edge of Magnolia Bluff. And there is this one elegant bluff left between the developed shorelines of Arroyos Beach and Seola Creek. Elsewhere they've been built on, excavated away, or locked behind seawalls.

Gravel was running in a continuous stream down the bluff while I watched - gradually adding to a talus cone on top of the drift logs.  Next door, the remains of someone's bluff-top backyard perch had landed in a jumble. The views from the homes along Marine View Drive must be spectacular, made more vivid by the excitement of participatory geomorphology.


The beach south of the Arroyos, all the way down to Seahurst Park in Burien, is marked by a broad sandy low tide terrace.  But to the north, the upper beach becomes coarser and the low tide terrace diminishes - it downright disappears in the vicinity of the previous post where the bathymetry drops off precipitously.  Longshore transport here is to the north (southerly waves dominate along this shoreline), but I suspect it's hard for sand to make it past the Arroyos without getting lost into deep water close to shore.  I wonder if that's why the beaches seem so different to the north?

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